Distribution Pattern of Heavy Metals in the Surface Sediments of the Jiaozhou Bay

Grain size analysis and chemical analysis of heavy metals are made for 312 surface samples of the Jiaozhou Bay. Nineteen samples of the waste water taken from the sewage discharge outlets along the eastern coast of the bay are also analyzed for heavy metals. Results show that heavy metals are richer in the east and poorer in the west of the bay. Sedimentary dynamic studies reveal that the distribution of heavy metals in the surface sediments of the Jiaozhou Bay is under the control of hydrodynamics.

The Morphology of Patterning with Pseudoplastic Metal Nanoparticle Fluids during Heat Treatment

A pseudoplastic metal nanoparticle fluid （PMNF） is used in nanoimprint to fabricate semiconductors and func- tional devices. The evaporation of the solvent and the sintering of the Au PMNF are investigated. The key parameters, which influence the morphology of patterning, such as the radius of metal particles, the concentra- tion of metal particles, the Hamaker constant of the solvent, viscosity of the fluids and the evaporation velocity, are analyzed. Based on a two-sphere sintering model, the equations are derived, which represent the relationships between the relative shrinkage and radius of the metal particles, sintering temperature and time. The optimal parameters for the heat treatment are provided in nanoimprint.

Dual-responsive fiber-reinforced hydrogel actuators by direct ion patterning

Nature inspired deformable heterogeneous smart hydrogels have attracted much attention in many fields such as biomedicine devices and soft actuators.However,normal spatial heterogeneous hydrogel structures can only respond to single factor and take one action as set in fabrication.Herein,we report a pre-stretched metal-liganded shape memory hydrogel with fiber reinforced,P(AAc-co-AAm)/CCNFs-Fe3+(CCNFs:carboxylated cellulose nanofibers,AAc:acrylic acid,AAm:acrylamide),which can conduct shape deformation by solvent induction and ultraviolet(UV)light.The deformation pattern could be programmed by the deposing of ferroin ions.Also,the pre-stretched shape memory hydrogels could effectively produce cyclic actuation or complex shape actuation by UV light.More importantly,combining the solvent response with the light response enabled complex reversible actuations,such as simulating the bending and unfolding of fingers.The addition of CCNFs significantly enhanced the mechanical properties of the hydrogels.The hydrogels with 3 wt.%CCNFs showed an elongation at break of about 500%and a significant increase in tensile strength of 8.7-fold to 1.55 MPa after coordination with metal ions,which was able to meet the mechanical requirements of the bionic actuated hydrogels.This work demonstrated that combining light-programmed and light-responsive shape-memory hydrogels,complemented by another independent response property,could achieve complex and reversible programmed actuations.

Dynamic metal patterns of wrinkles based on photosensitive layers

Regulating metal surfaces with micro-/nanoscale structures is of great significance for both material science and potential applications.However,the intrinsic properties of metals,such as fixed isotropic moduli and inflexible structures,in a sense present major limitations in developing next-generation smart patterned surfaces.In this work,a facile and general patterning strategy is proposed to endow insensitive metal surfaces with controllable spontaneous topologies and dynamic performance by exquisitely introducing an essential photosensitive interlayer.The arresting anthracene-containing photocrosslinking interlayer can selectively predetermine the anisotropic property of compliant bilayers without damaging metals’homogeneous properties,and realize a changeable stiff/soft layer.Furthermore,the mechanical transition mechanism of the self-adaptive wrinkling modes in metalbased trilayer systems is revealed to pave the pathway for regulating functional wrinkled metal surfaces.This photodriven metal patterning strategy can promote the development of brand-new methods for tuning the instability of multilayered materials,and be potentially applied in smart optical devices with dynamic reflectance,including light gratings and"magic"mirrors.

Palladium-assisted Metal Patterning on Polyimide Surfaces

A novel method of patterning high precision copper conductive micropatterns on flexible polymer substrate(polyimide)is developed.We utilized the coordination effect between palladium salts and pyridine structures to fix the palladium chloride(PdCl_(2))on the surface of polymer film while the 2,6-dimethylpyridine structures formed in the specific areas under ultraviolet light guaranteed the resolution of final patterns.Simultaneous thermal reduction of PdCl_(2) on the surface can be achieved in the process of thermal cyclization of the polymer substrate.As a consequence,the obtained polyimide(PI)film can be patterned with conductive copper micropatterns directly by electroless plating.In particular,we accomplished the deposition of high precision copper pattern with a minimum line width of 50μm and minimum line spacing of 20μm on PI thin films(thickness~10μm)by electroless plating.The prepared conductive copper micropatterns exhibit a low resistivity of 1.78μΩ·cm the same as the pure block copper.And the relationship between the structures of the polymer chains and the physical properties of polymer substrates,such as the dimensional stability,mechanical and dielectric properties were also discussed in detail.This simple and novel method of patterning metal on the polymer surface does not need to achieve the catalytic metal adhesion required for electroless plating at the cost of destroying the substrate surface and avoiding the introduction of unstable interlayers.This patterning method is compatible with the current roll-to-roll production process and can be used to develop high-performance micro-integrated circuits.

Self-nucleation of Patterned Polymer Thin Films Defined by Soft Lithography

The nucleation of crystals is often a determining step in the phase transition of materials,but it remains a challenge to control the density and specific location of nuclei simultaneously.Here we fabricated the isolated single crystals of uniform size with controlled number density and spatial distribution by self-nucleation of patterned dendritic crystals.Imprint lithography creates the periodic void space on the surface of poly(ethylene oxide)-b-poly(2-vinyl pyridine)(PEO-b-P2VP)block copolymer thin films and provides spatial redistribution of polymers,leading to the preferential nucleation and subsequent oriented growth of dendrites in the periodic arrays of imprinted lines.The morphology and thermal stability of the patterned crystals can be adjusted by tuning embossing conditions(e.g.,temperature and pressure).Furthermore,in the self-nucleation technique,the annealing temperature and heating rate are used as the feedback parameters to map the number density and spatial distribution of regrown single crystals.Such PEO-b-P2VP crystalline pattern can be used as a versatile template for large-area manufacturing of selective metal patterns for electronic devices and other applications.

Low threading dislocation density in GaN films grown on patterned sapphire substrates

The growth process of three-dimensional growth mode（3D） switching to two-dimensional growth mode （2D） is investigated when GaN films are grown on cone-shaped patterned sapphire substrates by metal-organic chemical vapor deposition.The growth condition of the 3D-2D growth process is optimized to reduce the threading dislocation density（TDD）.It is found that the condition of the 3D layer is critical.The 3D layer keeps growing under the conditions of lowⅤ/Ⅲratio,low temperature,and high pressure until its thickness is comparable to the height of the cone-shaped patterns.Then the 3D layer surrounds the cone-shaped patterns and has inclined side facets and a top（0001） plane.In the following 2D-growth process,inclined side facets coalesce quickly and the interaction of TDs with the side facets causes the TDs to bend over.As a result,the TDD of GaN films can decrease to 1×10~8 cm^（-2）,giving full-width at half maximum values of 211 and 219 arcsec for（002） and（102） omega scans, respectively.

Effect of metal surface morphology on nano-structured patterns induced by a femtosecond laser pulse and its experimental verification

The effect of material surface morphology on the periodic subwavelength of nano-structures induced by a femtosecond（fs） laser was investigated systematically from the initial surface roughness, the different scratches, the pre-formed ripples, and the ＂layer-carving＂ technology experiments. The results of the comparative experiments indicate that the initial surface conditions of the target surface have no obvious effects on the spatial structured periods（SSPs） and the ripple orientation of the periodic nano-structures induced by a fs laser, which agreed well with the foretold present surface two-plasmon resonance（STPR） model. Furthermore, different shapes of nanogrids with high regularity and uniformity were obtained by fs-laser fabrication.